ANALYTICAL APPLICATIONS OF ION-MOLECULE REACTIONS

This review covers applications of ion-molecule reactions for solving increasingly complex analytical problems. Because gas phase reactions are frequently fast and efficient, the use of ion-molecule reactions p rovides a diverse frontier for extending the boundaries of mass spectr ometry. Product distributions from ion-molecule reactions may provide key diagnostic information for structure identification, and particula r product ions may afford more structurally informative fragmentation patterns than those patterns of ions that are generated by conventiona l methods. Applications range from those areas involving tile developm ent of novel chemical ionization reagents that show structural specifi city upon reactions with analytes, to those areas in which ion-molecul e reactions are combined with collisionally activated dissociation in unusual sequences, to those areas involving ion-molecule reactions of species formed by laser desorption or electrospray ionization. In elec trospray ionization applications, the use of ion-molecule reactions al lows the concentration of ion cui-rent into fewer multicharged ions, p erm its the counting of acidic or basic sites, and provides indirect i nformation about protein structures and thermochemical data about indi vidual sites in large molecules. (C) 1997 John Wiley & Sons, Inc.